Power hydraulic hoist



June 1960 H. N. UNDERWOOD ETAL v 2,940,608

POWER HYDRAULIC HOIST 6 Sheets-Sheet 1 Filed March 30, 1959 n-vmwf'werzz'br's" 7 Dow Hereri N Underwood B05671 Q. 015672, and

- fiederz'cv Glass/i1;

June 14, 1960 H. N. UNDERWOOD EI'AL 2,9

POWER HYDRAULIC HOIST 6 Sheets-Sheet 2 Filed March 30, 1959 flrfieri N Underwood fiaberi Q'. OZJen. and freder'ic' G. Lass/g;

June 14, 1960 H. N. UNDERWOOD ETAL POWER HYDRAULIC HOIST 6 Sheets-Sheet 3 Filed March 30, 1959 June 14, 1960 H. N. UNDERWOOD EI'AL 2,9

POWER HYDRAULIC HOIST 6 Sheets-Sheet 4 Filed March 30, 1959 fizz/67222715: fiQrZerZ/Yllrzcierwood 11d F056;"? 4. Olsen and 107 Frederic/Q Glass/55y Film???- lW June 14, 1960 H. N. UNDERWOOD ETAL 2,940,608

POWER HYDRAULIC HOIST 6 Sheets-Sheet 5 Filed March 30, 1959 i 1 a w In ve rzl ars" firberijfllraderwaod 64 305671 d. 0l.sen and a: fiederc'c'i 6.5m:

June 14, 1960 H. N. UNDERWOOD EI'AL 2,940,608

POWER HYDRAULIC HOIST 6 Sheets-Sheet 6 Filed March 30, 1959 mm; M 1m Z vfw Z2 NEWER HYDRAULIC HOIST Herbert N. Underwood, Qhicago, Robert A. Olsen, La

Filed Mar. 39, 1959, Ser. No. 393,019

12 Claims. (Ci. 212--124) This invention relates to a power hoist of the electrohydraulic servo type.

It is an object of this invention to provide an improved hoist comprising a stationary part and a movable part, the stationary part constituting a piston and the movable part including a cylindrical chamber slidably movable over the piston.

It is another object of this invention to provide in a hoist of the present type a source of fluid pressure comprising a motor driven pump supplying fluid to an accumulator having air therein for maintaining the fluid under pressure so that the movable part of the hoist may be moved with respect to the stationary part even though the motor is inoperative at the time.

It is another object of this invention to provide a control handle carn'ed by the movable part of the hydraulic hoist which so controls fluid pressure application to the cylindrical chamber that the movable part of the hoist moves upwardly when an upward force is :put on the handle and moves downwardly when a downward force is put on the handle and at a rate depending on the pressure exerted on the handle.

It is another object of this invention to provide a control handle carried by the movable part and which has a spring biased part at the inner face of the gripping portion of the handle and is so constructed that when the handle is firmly gripped, it will be locked in a neutral position so that the operator may move the hoist in a horizontal plane handling a work piece without accidentally moving the handle up or down which would inadvertently cause upward or downward movement of the movable part.

It is also an object to provide adjusting means for centering the control handle with respect to a neutral position.

It is a further object of this invention to provide conduits for carrying the hydraulic fluid, which are within the stationary and movable parts thereby providing an improvement over customary constructions which place these conduits or leads on the outside where they may be damaged or become entangled under working conditions.

it is still a more particular object of this invention to provide a carriage from which the stationary part is suspended and which supports the components of a power source which is utilized in moving the carriage on rails by fluid pressure supplied by the operation of a valve which causes the carriage to move on the track in the direction in which pressure is exerted against the movable part.

This invention consists of the novel constructions, arrangements and devices to be hereinafter described and claimed for carrying out the above-stated objects and such other objects as will be apparent from the following description of a preferred form of this invention, illustrated with reference to the accompanying drawings, wherein:

Figure l is a view in elevation, showing apreferred United States Patent Patented June 14, 1960 ice embodiment of the hoist embodying the present invention, and indicating the manner of supporting a work piece;

Figure 2 is a plan view bringing out to advantage the power pack arrangement carried on an overhead track and showing parts thereof;

Figure 3 is a side view of the power pack taken on line 33 of Figure 2, showing the electric motor, master block, sump tank, and other components; I

Figure 4 is a cross sectional view taken on line 4-4 of Figure 2;

Figure 5 is an end view of the power pack showing some of the internal parts and the overhead track in cross section;

Figure 6 is an enlarged vertical cross section view of the piston rod, piston head, cylinder and universal coupling assembly, showing to advantage some of the internal parts;

Figure 7 is an enlarged cross section viewof the lower part of the cylinder together with the housing containing a valve mechanism and other parts;

Figure 8 is a cross section view taken on line 8- 8 'of Figure 7;

Figure 9 is an enlarged cross section view taken on line 99 of Figure 7;

Figure 10 is a cross section view taken on line 10-40 of Figure 9;

Figure 11 is an enlarged cross section view taken line 11-11 of Figure 5;

Figure 12 is an enlarged cross section view'taken-on line 12-12 of Figure 3; and

Figure 13 is a schematic diagram of the hydraulic system of this invention.

Like characters of reference designate like parts in the several views.

Figure l is a general assembly view in elevation of the present hoist carried on an overhead track 10, broadly on the piston head 12 when the control handle 14 is moved upward and to cause the cylinder 13 to :move down when the control handle 14 is moved downward. A hook 15, adapted to support a work piece 16, is -attached to the lower end of the cylinder 13.

Referring now to Figure 2, the hydraulic pressure power pack 9 comprises a carriage :17 having a hydraulic accumulator 18 attached thereto on one side by a pair of straps =19, and a master block 20 attached to the other side, carrying an electric motor 21 and a sump tank :22 on opposite sides thereof.

The carriage 17 comprises supports 23 and 24 which carry wheels 25, 26, 27 and 28 at their ends that are operable on the overhead track .10. Wheels 27 and 28 have gears 29 and 30, respectively, attached to their inner faces, and are operably connected with respect to a fluid pressure power source, hereinafter more fully explained, for rotating the wheels .27 and 28 and :thereby providing lateral movement of the hoist on overhead track 10.

The master block 20, Figure 3, encloses a hydraulic pump 31, which is driven by the electric motor 21. An intake tube 32 is provided for the hydraulic pump al as a means for supplying fluid from the sump tank zl. A pressure passageway 33 serves as an outlet from thehydraulic pump 31 to provide fluid under, pressure for the operation of the hoist as hereinafter more fully described.

A check valve' 34is provided to prevent the return of fluid under pressure to' the hydraulic pump 31,.and a pressure relief valve 35, placed in the sump tank 22, is alsoprovided withrespect to the pressure passageway l'33 andserves to prevent excessive pressure build-up by opening at a predetermined pressure and returning the over-flow fluid to the sump tank 22, as shown in the schematic diagram of the hydraulic system, Figure 1 3. A traverse valve mechanism. 36, connected with respect to the support 24 is provided as a means for the operation of, and the control of the lateral movement of the hoist on overhead track v10 as hereinafter more fully explained. The traverse valve mechanism 36 which is 7 shown in detail in Figure 11, and will be hereafter more fully described, is provided with a valve spool 37 which 7 is connected by a link 38 to arm 39 which is fixed with "respect to a cross 40 of a universal coupling 41 and more clearly shown in Figure 12. The valve spool 37,

is so linked with respect to the universal coupling 41, so that it will move in unison with the piston rod 11 when 7 it isswung linearly with respect to the overhead track 10.

-A traverse hydraulic motor 42, Figure 5, is provided with a driveshaft 43 whichcarries pinion gears 44 and 45 that'mesh with the gears 29 and 30, respectively, thereby providing the means for driving the wheels 27 and 28 on overhead track. 10 when the traverse hydraulic motorr42 is supplied with fluid under pressure. Conduits for supplying this fluid under pressure to the traverse hydraulic motor 42 comprise pressure tubing 46 connectedbetween the'hydraulic accumulator 18 and the traverse valve mechanism 36 and passageways 47 and 48 connected to the traverse hydraulic motor 42 which supply it with fluid under pressure for driving it in one of hydraulicfluid into the area at the closed end of the cylindrical sleeve 79. An annular groove 91'is provided at one end of the valve spool 78 as an engaging means for a pin 92, Figure 8, which is connected at its ends across the gap at a reduced diameter b, of a shaft 93, positioned across the remote ends of the control handle 14, and fastened thereto by pins 94. The shaft 93 is rotatably supported with respect to the hoist valving mechanism 62. It istherefore apparent that up or down movement of the control handle 14 will cause movement of the valve spool thereby providing means for the operation of the hoist valving mechanism 62. A pin 95 is also provided which is connected at its ends across the gap at a reduced diameter 0 of vthe shaft 93 for use in direction or the other, depending upon the position of a valve spool '37. 'A sump return 49 is provided for the return of the fluid from the traverse valve mechanism 36.

f Referring back to Figures 6 and l2,' a more detailed view of the universal c011pling 41 is shown to comprise V a yoke'50 attached to the upper end of the piston rod 11 and has yoke arrns'51 and 52 with cylindrical bores 7 153 and 54, respectively for receiving trunnions 55 and 56, respectively. A pair of trunnions 57 and 58, fixed at 7 right angles with respect to yoke arms 50 and 51 are ,also provided and" are carried in cylindrical bores 59 a and 60 in the supports 23 and 2 4, respectively, thus'providing a coupling which permits the cylinder 13 and its supporting piston rod 11 to swing in alldirections. accumulator tube 61 serves as' a conduit from the hydraulic accumulator 18 to carry fluid under pressure to ial'hoist'valving mechanism'62, Figure 7 through a series of passageways consistingtof passageway 63, passageway 64 in trunnion 57, passageway'65 in trunnion 56, passage- 1 way 66in yoke arm.52, piston' rod'passageway 67, tube passageway 68, and valve passageway 69, shown in Figures'6 and 9. A'passage 7-1 communicating with the sump tank 22 provides communication between the hoist ,1 .valving mechanism 62 and the sump tank 22 in conjunc- 1 tion with passageway 70 in trunnion 58, passageway 72 i in trunnion 55," passageway 73 in yoke arm 51, piston connection with adjusting the control handle 14 with respect to a neutral position hereinafter more fully explained; An inner gripping means 96 generally rectangular in configuration is provided within the confines of the control handle 14 and is slidable with respect to the sides thereof and spaced from the inner face of the end of the control handle 14 and biased with respect thereto by springs 97. An eccentric shaft 98 is connected across the far ends of the inner gripping means 96 by clamps 99 which are fastened with screws 100. A protruding part 101, extending laterally from a valve housing 102 of the hoist valving mechanism 62 is provided withan irregular shaped opening 103 for receivihg the shaft 98; The irregular shaped opening 103 comprises vertically'extending recesses 104 and 105 in the protruding part 101, for receiving the eccentric shaft 98 when the control handle 14 is moved'up or down and thereby providing a means for limiting the upward and downward movement of the control handle 14. The irregular shaped opening 103 also comprises a forwardly extending recess 106 in the protruding part 101, for receiving the eccentric shaft 98 when the inner gripping means 96 is squeezed against the bias of the'springs 97, thereby locking the handle a 108 in the valve housing 102 having a reduced diameter 109 at its upper end thereby providing a shoulder 110 as Q a buttress for a Washer 111. A shaft 112 having a lug 'portion 113. at its lower. end, is provided with a washer 114 that rests on the top of a sleeve 115 and the top of the lug portion 113 which is encompassed by the sleeve 115 which in turn is carried within the lower end of the cylindrical bore 108. The shaft 112 is provided with a coil spring 116 biased between the washers 1'11 and'114 and held captive by a snap ring 117 around the upper end of the shaft 112 above the washer 111. The sleeve 115 is locked within the cylindrical bore 108 by a snap ring 118.in the lower end of the vertically extending cylindrical bore 108. The adjusting means 107 is also provided with an adjusting screw 119, which is threaded into the lug portion 113 and is provided with an annular groove 120 which engages the pin 95 connected to the rod cylindrical passageway 74, piston passageway 75,

; cylinder sump passageway 76, and valve sump passage- The hoist'valving mechanism 62 'is'provided with a valve spool 78 .s lidably operable within a cylindrical sleeve 79 having a port"-80 therethrough for the passage of fluid from the'valvepassageway 69. The cylindrical sleeve 79. is provided with apair of shaped openings j81 through opposite sides thereofhaving 'two pairs of .tri-' angular indents 82 and 82a. A passageway 83 is communicable with the pair of shapedlopenings 81 and an annular passageway 84, which communicates with' an annular control chamber 85.,byvirtue of ports 86, Figure p 6. The valve spool'78 is provided with lands 87 and 88having a valve pressure chamber 89 between them. H

."AI sump passageway 90 through the center of tlie spool v a P v de a att m ssin p s ble ssaa shaft 93, Figure 8. Thus, it is apparent that by turning the adjusting screw 119 in one direction or the other, the 'end of the control handle 14 will move upwardly or "downwardly, depending upon the direction the adjusting screw .119 is turned and therefore provides a; means for positioning the control handle'14 in a neutral position with respect to the valve spool 78 which controls the power supply of fluid for raising or lowering the cylinder 13. In this connection attention is again directed to the inner gripping means 96 shown in Figures 7 and 8 which also incorporates a means for aligning the eccentric shaft 98, if necessary, with the forwardly extending recess 106 after the control handle 14 has been adjusted to a neutral position; In the event of inaccuracies with respect to related parts ,the eccentric shaft 98 may not be properly lined up with the forwardly extending recess 106 and consequently in the process of locking the control handle 14 as described above, the eccentric shaft 98 will be deflected up or down thereby moving the control handle 14 from its neutral position and inadvertently supplying fluid under prmsure with respect to the cylinder 13 and causing it to move. Therefore, the shaft 98 is made eccentric so as to provide corrective means for such possible inaccuracies and may be' rotated so as to line up with -the forwardly extending recess 166 and held in that position by fastening the clamps 99 by means of the screws 109.

Referring now to Figure 11; the traverse valve mechanism 36 is provided with a cylindrical bore 121 having disposed therein the valve spool 37 which is provided with lands 322, 123, 124 and 125, thereby providing sump chambers 126 and 127 and a pressure chamber 128 therebetween. The cylindrical bore 121 is provided with a passageway 129 which is communicable with the hydraulic accumulator 18 through pressure tubing 46 and accumulator tube 61 for supplying fluid under pressure to the pressure chamber 128. The cylindrical bore 121 is provided with another passageway 130 which is connected to the sump .tank 22 by sump return 49 thereby providing a return for hydraulic fluid to the sump tank 22 from sump chambers 126 and 127 respectively. The cylindrical bore 121 is also provided with ports 134 and Port 134 is connected to passageway 48 for providing fluid under pressure from the pressure chamber 128' to the traverse hydraulic motor 42 for turning it in one direction and the port 135 is connected to passageway chamber 128 for turning the traverse hydraulic motor 42 in the other direction.

Referring back to Figure 5, a pressure switch 136 is shown which comprises a cylinder 137 provided with a :piston 138 operable therein, which under the influence of pressure built up in a pressure switch passageway 139, moves against the bias of a spring 140 and moves a reaction rod 141, against a button 142 of a micro switch 143, thereby shutting ofl the electric motor 21. The pressure switch 136 also has an adjusting screw 144 for adjusting the micro switch 143 so as to shut off the electric motor 21 at any desired predetermined fluid pressure.

The operation of the hoist, which will be more specifically described hereinafter, is as follows: Pressure is built up in the hydraulic accumulator 18 by means of the hy draulic pump'3l driven by the electric motor 21 whereby the hoist is prepared for operation. When the operator moves the control handle 14 upward, the hoist valving mechanism 62 provides hydraulic pressure so as to cause --the cylinder 13 to move upward and conversely when the control handle 14 is moved downward the hoist valving mechanism 62 provides hydraulic pressure so as to cause cylinder 13 .to move downward. When movement of :the hoist on the overhead trackgit) is desired, the'operator pulls against the control handle 14 so as to swing the cylinder i3 and piston rod 13 slightly to the right as viewed from Figure 1, thereby actuating the traverse valve mechanism 36 whereby fluid under pressure is provided for the traverse hydraulic motor 42 which provides the power for moving the hoist to the right on overhead track and conversely, when the operator pushes against the handle to the left, the hoist will move to the lefit on overhead track iii. Thus, it is apparent that the operator may handle a worl: piece with the use of one hand only and with but slight exertion, as power is supplied for lifting and lowering a work piece and also for moving it in either direction on the overhead track 10. In this connection attention is directed to .the inner gripping means 96 as a means for locking the control handle 14 against inadvertent up and down movement when the hoist is power driven on the overhead track 18.

More specifically, when the electric motor 21 is connected to a source of power the hydraulic pump 31 is driven and picks up fluid from the sump tank 22 by means of-intake tube 32-and supplies the fluid thus picked up to the hydraulic accumulator 18 through passageways '33, 64, 63 and accumulator ttube 61. A check valve 34 is provided to prevent the fluid from returning to the hydraulic pump 31 and a pressure relief valve 35 is also provided to prevent the pressure build up beyond a predetermined level. If pressure is inadvertently built up beyond that level, the pressure relief valve 35 opens and the fluid is returned to the sump tank '22. The pressure switch 136 has incorporated therein a micro switch 143 for shutting off the electric motor '21 when pressure is built up to a predetermined level. This is accomplished by means of the piston 138 which under the influence of pressure in the pressure switch passageway 139 moves against .the bias of the spring 140 and pushes the reaction rod 141 against the button 142 of the micro switch 143 thus breaking the electrical connection.

Fluid under pressure in the hydraulic accumulator 18 is thus made available for the operation of the hoist for lifting and lowering a work piece and also for movement of the hoist on the overhead track 10. The hoist valving mechanism 62 serves to control the up and down movement of the cylinder 13 in the handling of a work piece, and the traverse valve mechanism 36 serves to control the movement of the hoist on overhead track 16. More specific detail with respect to both of these operations follows.

First, with respect to the up and down movement of the cylinder 13; fluid under pressure is supplied to the valve pressure chamber 89 of the hoist valving mechanism 62. by the hydraulic accumulator 18 through the accumulator tube 61, and thence through passageways 63, 64, 65, 66, 67, 68 and 69 and port 84) in the cylindrical sleeve 79. When it is desired to move the cylinder i3 upward, the control handle 14 is moved upward, thereby rotating the shaft 93 counter-clockwise as viewed in Figure 13 and the pin 92 being in engagement with the annular groove 91 of the valve spool 78, moves the valve spool 78 upward thus moving the land 87 upward which exposes the shaped opening 81, at the pair of triangular indents 82, to the valve pressure chamber 89 thereby opening a passageway for the fluid under pressure to the annular passageway 84 by means of which the fluid under pressure passes through port 86 into the annular control chamber 85 and exerts pressure therein. It will be observed by referring to Figure 6 that the top wall of the annular control chamber 85 is a part of the structure of the cylinder 13 and the lower wall thereof a part of the piston head 12, whereby under the influence of pressure between these walls the cylinder 13 moves upward. Conversely, when it is desired to move the cylinder 13 downward, control handle 14 is moved downward, thereby reversing the above mechanical sequences and moves the land 87 downward thereby closing the pair of triangular indents 82, thus shutting oflf fluid under pressure to the annular passageway 84, and the other pair of triangular indents 82a are exposed to the valve sump passageway 77 and the annular passageway 84 thus permitting the fluid in the annular control chamber 85 to drain back to the sump tank 22 through valve sump passageway 77 by way of cylinder sump passageway 76, piston passageway and passageways 74, 73, 72, 70 and 71; and the fluid under pressure from the hydraulic accumulator 18, through the accumulator tube 61 and the passageways 63, 64, 65, 66, 67, 68 and 69 which provides reaction pressure with respect to the lower end of the cylinder 13, thus lowering the cylinder 13.

Now, more specifically with respect to the horizontal operation of the hoist on overhead track 10; fluid under pressure is supplied from the hydraulic accumulator 18 through the accumultaor tube 61 and thence through pressure tubing 45 and passageway 129 -to the pressure chamber 128 of the traverse valve mechanism 36 thus providing a source of fluid under'pressure for the hori- When it is desired to move the hoist to the left on over- ,shfliciently to the left, uncovers the port 134 as the land '125, a part of the valve spool 37, moves to the left r whereby communication is established with the passageway 48, and fluid under pressure from the pressure chamber 128 is supplied to the traverse hydraulic motor 42. The relationship'of the drive shaft 43 to the traverse -,hydraulic motor 42 is such-that the drive shaft 43 and t clockwise.

the pinion gears and 45 which are fixed thereto rotate Thepinion gears 44' and 45 being meshed with gears 29 and 30 respectively which in turn are fixed --to the wheels 27 and 28 respectively will cause these -t wheels to turn in a counter-clockwise direction and move the hoist to the left on overhead track l9. Conversely,

pulling on the control handle 14 toward the right causes a the -valve' spool 37 and the land 124, 'a part thereofflto :,move" to the right and uncover port 135, thus establishing communication between the preSsurechamber-IZS and the passageway 47 whereby fluid under pressure is a Isupplied to the opposite sides of the 'traverse hydraulic motori 42 thereby causing a sequence of events opposite .10 :those 'justen'umerated' and hence cause the hoist to moveto the right on overhead track 10.

It should be 8 necting said annular control chamber with said internal e sump passageways when said handle is moved downward to cause said cylinder to movedownward.

2. In a power hoist having a power pack supported by a carriage provided with wheels operable on an overhead 'track, the'said power pack comprising an electric motor;

apump, a sump tank and an accumulator as a 'sourceiof fluid pressure for the operation of saidhoist; the combi nation of a piston rod suspended from said carriage by means of :a universal coupling; 'a piston head at' the remote end of said piston rod; a cylinder slidably movable 1 over said piston head; an annular control chamberbetween said piston head and the. top of said cylinderga metal structure at the lower end of said cylinder for carrying a workpiece; a valving mechanism also carried at the lower end of said cylinderginternal pressure ipassageways in said cylinder, piston'rod, piston head and universal coupling connected between said accumulator tank and said'valving mech'anism;,internal sump passageways in said cylinder, piston rod, piston head and universal V i coupling connected'between said sump tank and said valv- L ingmechanism; and acontrol handle operably associated ward and forcutting ofitsaidfiuid under pressure'to-s'aid r with said valving mechanism for supplying said-fluid :under pressure to said annular control chamber for moving said cylinder upward when said'ha'ndle'is movedfilpr "annular control chamber and'con necting said'iannular Qcontrol chamber with said internal sump passageways t noted that when fluid under; pressure is supplied through passageway 48,. the passageway 47 serves as a return of the'fluid to the sump chamber 127 and thence by way when said handle is moved downward to causesa id 'cylinderto'mov'e downward. 2

3. In a power hoist havingfa power pack supported r b'ya carriage'providedwith wheels operable on an overof outlet'133, channel 131 and outlet 132 to passageway -w 130V-and tube 49 and thence back to the sump tank 22.

Conversely," when fluid under pressure is supplied to the head track, said power'pack comprising an electric motor, apump a sump'tank and an' accumulator as a source of fluid pressure for the operation of said hoist; the com- "bination of a" piston rodtsuspended from said carriage'hy traverse hydraulic motor 42 through passageway 47 to' a cause rotation in the other directiom'the passageway'48 then serves as fa return for the fluid to the sump tank 22 by way of sump chamber 126, outlet 132 and passageway V 130 and tllbe 49;

It is contemplated that fluid passageways which have mo'vernent 1 of parts at their connections and other components where fluid loss may 'occur', be, sealed against fluid loss by readily "available means such as 0 rings.

We wish it' to be-understood that our invention is not ;to--be limited'to the specific constructions and arrarige ments shown and described; except only in so foras the ;appended claims may be so limited as it will be understood to those skilled in the art that changes may be made Q without departingrfromrtheprinciples of'the invention.

f We claim: 1 V r a a p t V In-a power hoist having a power pack supported e by a carriage provided with wheels operable 'on an overhead? track,- the said power pack comprising an electric motor, a pump, a sump tank and an accumulator as a source of fluid pressure for 'the operation of sahidhoist; the combinationof a piston rod suspended from said carriage by means of a universal coupling; a piston head at the'remote' end of said piston'rod; a cylinder slidably mova'ble'over said'piston head; an annular control chamber between'said pistonhead and the top of said cylinder; a metal structure at the lower'end of said cylinder for carryingawork piece; a valving mechanism also carried a at the lower end of said cylinder; internal pressure passageways in said cylinder,- piston rod, and piston head connected between-said accumulator and said valving mechanism; internal'sump passageways in said cylinder,

piston head and piston rod connected between said sump V tank and said valving mechanism; and a control handle a erahl associated with said valvin "mechanism for su l V u op y g p .smew, depending upon which dII'GCLlQIl said screw is plying said fluid under pressure to said annular control L'chamber for moving said cylinder upward when said :Jha'ndl'e is movedupward and for cutting ofi said fluid p I V 1 Qundergpressure to said t itium new; chamberandcom I 21re egti rva msnt amsm- J 1;;

meansof a universal coupling; a piston head fixed to the remote end of said piston rod; a cylinder slidably movable over said piston head; an annular control chamber betweensaid piston head'and top of saidcylinder; a metal structure at the lower end of said cylinder for carrying a work piece; a valving mechanism also carried at the 1 lower end of said cylinder; conduit means connecting said -fluid pressure source with said'valving mechanism; conduit means connecting said sump tank with saidvalving j mechanism; a control handle generally of rectangular configuration, comprising a shaft'connected across the remote end thereof and pivotally supported with respect to said valving mechanism,'said control handle being oper'ably connected with said valving mechanism fortsupplying said fluid 'under pressure to said annular control chamber for moving said jc'ylinderupward wheni said handle is moved upward and for cutting on said fluid under pressure to said annular control chamber andcon- 'ne'c tin'g said annular control chamber with said sump tank when said handle is moved downward to cause said cylinder to move downward; a valve adjusting means with respect'to said valving mechanism comprising a vertically extending cylindrical bore having a reduced diameter at its upperend; a sleeve within said cylindrical bore; a shaft having an enlarged lug portion slidably fitting within said sleeve; a first washer around said shaft resting on said sleeve; a second washer around said shaft .in the upper end of said cylindrical bore; a snap ring around the upper end of .said'shaft above said second "rwasher; a spring biased between said washers; a screw threaded into said lug portion; an annularlgroove around :said screw for engaging apin fixed to said shaft that is connected across said control handle whereby saidshaft is rotated in one direction or the other onturning said fturned, thereby providing adjusting means for locating ,A power hoist as set forth in claim 3 wherein said control handle is provided with an inner gripping means generally of rectangular configuration positioned within the inner periphery of said control handle and slidable with respect to the sides thereof; springs biased between said inner gripping means and the end of said control handle; said inner gripping means being provided with a shaft clamped across the ends thereof adjacent said valving mechanism; a housing for said valving mechanism, and a protruding part extending from said housing having an irregular shaped opening therethrough comprising a forwardly extending recess for receiving said shaft clamped across said inner gripping means so that when said control handle including said inner gripping means are grasped firmly said shaft clamped across said inner gripping means is moved into said recess and said control handle is locked in said neutral position.

5. A power hoist as set forth in claim 3 wherein said valving mechanism comprises a valve spool having an annular groove at one end thereof operably engaged with said shaft that is fixed across the remote end of said control handle whereby said valve spool may be selectively moved for controlling said fluid pressure.

6. In a power hoist having a power pack supported by a carriage provided with wheels operable on an overhead track, the said power pack comprising an electric motor, a pump, a sump tank and an accumulator as a source of fluid pressure for the operation of said hoist; the combination of a piston rod suspended from said carriage by means of a universal coupling; a piston head fixed to the remote end of said piston rod; a cylinder slidably movable over said piston head; an annular control chamber between said piston head and the upper end of said cylinder; a metal structure at the lower end of said cylinder for carrying a work piece; a valving mechanism also carried at the lower end of said cylinder; internal pressure passageways in said cylinder, piston rod, and piston head, connected between said accumulator and said valving mechanism; internal sump passageways in said cylinder, piston rod and piston head connected between said sump tank and said valving mechanism; a control handle having a normally neutral position operably associated with said valving mechanism for supplying said fluid under pressure to said annular control chamber for moving said cylinder upward when said control handle is moved upward and for cutting off said fluid under pressure to said annular control chamber and connecting said annular control chamber with said internal sump passageways when said handle is moved downward to cause said cylinder to move downward, said handle being generally of rectangular configuration having an inner gripping means generally of rectangular configuration serving as an inner peripheral part thereof and linearly slidable with respect to the sides thereof; a valve housing for said valving mechanism provided with a protruding part extending therefrom having an irregular shaped opening therethrough said irregular shaped opening comprising a forwardly extending recess in said protruding part; a shaft fastened at each end by clamps to the ends of said inner gripping means adjacent said valving mechanism movable into said forwardly extending recess when said control handle is gripped firmly whereby said handle is locked in said neutral position.

7. A power hoist as set forth in claim 6 wherein the shaft is of eccentric construction so that it may be rotated when said clamps are loosened for alignment with said forwardly extending recess when said handle is in said neutral position and fastened by said clamps when so aligned.

8. In a power hoist having a power pack supported by a carriage provided with wheels operable on an overhead track said power pack comprising an electric motor, a pump, a hydraulic motor, a sump tank, and an accumulator as a source of fluid pressure, the combination of a piston rod suspended from said carriage by means of a universal :coupling; a piston head carried :B -saiapisten rod; :a :cylinder slidably movable over said piston head; an annular control chamber betweensaid piston head and the upper end of said cylinder; a metal structure at the lower end of said cylinder for carrying a work piece; a valve mechanism also carried at the lower end ofsaid cylinder; pressure passageways connecting said accumulator with said valving mechanism; sump passageways connecting said sump tank with said valving mechanism; a control handle operably associated with said valving mechanism for supplying fluid under pressure .to said annular control chamber for moving said cylinder 'so that when said handle is moved upward fluid under pressure is supplied to said annular control chamber and moves said cylinder upward and when said handle is moved downward the supply of said fluid under pressure to said annular control chamber is out 01f and said annular control chamber is connected with said sump passageways for moving said cylinder downward; a traverse valving mechanism fixed with respect to said carriage; and linkage means between said traverse valving mechanism and said universal coupling affective on said traverse valving mechanism to connect said fluid under pressure to said hydraulic motor for moving said wheelsand thereby cause said carriage to travel in one direction on said track when said piston rod is swung in said one direction and for causing said carriage to travel in the opposite direction when said piston rod is swung in said opposite direction.

9. In a power hoist the combination of a power pack supported by a carriage and comprising an electric motor, a hydraulic pump, an accumulator, a sump tank and a hydraulic motor as a source of fluid pressure; a suspended part; a universal coupling connecting said suspended part to said carriage; a movable part adapted to carry a work piece said movable part having a cylindrical chamber therein slidably movable over said suspended part; wheels on said canriage operable on an overhead track; a valving mechanism fixed with respect to said carriage; passageways connected between said valving mechanism and said source of fluid pressure; and linkage means between said valving mechanism and said universal coupling effective on said valving mechanism when said suspended part is pushed linearly in one direction with respect to said track whereby fluid under pressure is provided for said hydraulic motor for moving said wheels thereby causing said carriage to travel in said one direction on said track when said suspendedpart is pushed in said one direction and for causing said carriage to travel in the opposite direction when said suspended part is pushed in said opposite direction.

10. A power hoist as set forth in claim 8 wherein the said hydraulic motor drives a shaft to which are affixed a pair of pinion gears each meshing with one each of a pair of gears, each of which is fixed to one each of said pair of wheels.

11. A power hoist as set forth in claim 8 wherein the said universal coupling comprises a pair of trunnions, one each of which is journaled with respect to opposite sides of said carriage and at substantially right angles with respect to said track, and wherein said linkage is. connected with respect to one of said trunnions.

12. In a power hoist having a power pack supported by a carriage provided with wheels operable on an over-- head track said power pack comprising an electric motor, a pump, a hydraulic motor, a sump tank, and an accumulator as a source of fluid pressure the combination of a piston rod suspended from said carriage by means ofa universal coupling; a piston head at the remote end of said piston rod; a cylinder slidably movable over said piston head; an annular control chamber between said piston head and the upper end of said cylinder; a metal structure at the lower end of said cylinder for carrying a work piece; a valving mechanism also carried at the lower end of said cylinder; internal pressure passageways in said.

cylinder, piston rod, pistonihea'd anduniversalcoupling :on nected together between said accumulator'andsaid valving mechanism; internallsump'passageways 'in' said :cylinder; piston rod, piston head and universal coupling connected together between said sunip' tank. and said 5 valving mechanism; a control handle operably associated owithsaidyalving mechanism for supplyingfluid under 7 pressure to said annular control-chamber for moving said,

cylinder so'that when said handle is movediupward fluid under pressureis supplied to said annular controlcham 10 traversevalving mechanism and said universal coupling efiective on said traverse valving mechanism toconnect said fluid under pressure to said hydraulic motor for moving said wheels and thereby cause said'carriage to travel in one direction on said track when said piston rod is swung in said one direction and for causing said carriage to travel in the opposite direction'on said track when said piston rod .is swung in said opposite direction.

References'Cited'in the file of this patent UNITED STATES, PATENTS V Halsey Nov. 21, 1899 637,333 646,458 Pendrick Apr. 3, 1900 2,574,131 Steinbrecher Nov. 6,, 1951 FOREIGN PATENTS I V 1,126,542 France July. 30,1956 

